Prime Minister Boris Johnson has warned People should not get "carried away with over optimism" after the UK approved its first coronavirus vaccine,.
He said it did not mean "our struggle is over", saying parts of the economy still faced tough restrictions.
England's deputy chief medical officer Jonathan Van-Tam urged patience over the rollout of the Pfizer/BioNTech jab, which begins early next week.
"It's going to take months, not weeks", he said.
A further 648 deaths within 28 days of a positive Covid-19 test were recorded in the UK on Wednesday, with another 16,170 cases reported.
Speaking at a Downing Street news conference, Mr Johnson said the decision to approve the Pfizer jab by regulator MHRA came amid "immense logistical challenges" in getting doses to vulnerable groups.
The vaccine needs to be stored at around -70C and comes in packs of 975 doses, which cannot yet be split into smaller batches.
Those who receive it will need a a second dose 21 days later to receive full protection.
"It's going to continue to be tough for some sectors - but until the vaccine is deployed our plan relies on all of us making sacrifices to protect the ones we love," Mr Johnson said.
Meanwhile, Labour's leader Sir Keir Starmer said the vaccine roll-out would require the "best of Britain" as he called for cross-party consensus on communications about the effort.
